The reduction in memory cell and other circuit size implemented in high density dynamic random access memories (DRAMs), static random access memories (SRAMs), logic and other circuitry is a continuing goal in semiconductor fabrication. Implementing electric circuits involves connecting isolated devices through specific electric paths. When fabricating silicon and other semiconductive materials into integrated circuits, conductor devices built into semiconductive substrates need to be isolated from one another. Such isolation typically occurs in the form of LOCOS grown field oxide, and more recently in isolation trench and refill field isolation regions.
Conductive lines, for example transistor gate lines, are formed over substrates. Some lines run globally over large areas of the substrate. Others are much shorter and associated with very small portions of the integrated circuitry. This invention was principally motivated in making processing and structural improvements involving local interconnects.